Sulfur dioxide is a convenient and widely used source of the sulfonyl functional group. Specifically, Sulfur dioxide participates in cycloaddition reactions with dienes.[3]
The industrially useful solvent sulfolane is prepared by addition of sulfur dioxide to buta-1,3-diene followed by hydrogenation of the resulting sulfolene.[4]
Sulfones have been prepared by nucleophilic displacement of halides by sulfinates:[8] In general, relatively nonpolar ("soft") alkylating agents react with sulfinic acids to give sulfones, whereas polarized ("hard") alkylating agents form esters.[9]Allyl, propargyl,[10] and benzyl[11] sulfinates can thermally rearrange to the sulfone, but esters without an activated bond generally do not rearrange so.[12]
Sulfolane is used to extract valuable aromatic compounds from petroleum.[4]
Polymers
Some polymers containing sulfone groups are useful engineering plastics. They exhibit high strength and resistance to oxidation, corrosion, high temperatures, and creep under stress. For example, some are valuable as replacements for copper in domestic hot water plumbing.[15] Precursors to such polymers are the sulfones bisphenol S and 4,4′-dichlorodiphenyl sulfone.[16]
